The present invention relates generally to the field of heat exchange in industrial processes and in particular to a new and useful heat pipe structure.
Heat pipes are known in the field of heat exchange. Heat pipes are conventionally cylindrical, with circular cross-sections. Caps are provided at each end to form a closed vessel. A wick is provided through the center of the pipe. A working fluid is provided inside the heat pipe vessel.
One end of the pipe is an evaporator end and is exposed to a warm substance, such as hot air. The other end is a condenser end and is exposed to a cooler substance. The heat at the evaporator end causes the working fluid to evaporate and travel to the opposite end of the heat pipe, to the condenser end. At the condenser end, the working fluid gives up the heat to the heat pipe material, exchanging heat with the cooler substance, and condenses to a fluid, which is then wicked back to the evaporator end to repeat the cycle. When the working fluid is selected properly, heat can be efficiently transferred in this manner between substances having a relatively small temperature difference, as well as those with larger temperature differences.
Non-circular tubes are known for use in heat exchangers. Heat exchanger tubes are distinct from heat pipes, however, as they lack the internal structure of a heat pipe and cannot be used as a self-contained heat exchange system. In particular, past designs are not well adapted to including a wick, which is an essential element of a heat pipe, and required for it to function.
For example, U.S. Pat. No. 5,279,692 discloses an elliptical tube having several discrete, generally triangular cross-section flow passages through the tube.
Non-circular cross-section tubes used in boilers and furnaces having cross-sectional stiffeners are known. U.S. Pat. No. 5,511,613 discloses a non-circular cross-section tube used in a boiler heat exchanger. The tube may have cross-sectional stiffeners inside the tube. The stiffeners are different shapes and form restrictive barriers inside the tubes.
Elliptical-shaped pipes in particular have properties which are beneficial for use as heat pipe vessels. A larger surface area is provided for condensation to occur on. The narrowed width concentrates and minimizes the amount of working fluid in liquid form in the evaporator end of the heat pipe.